CVE - CVE-2021-47603

CVE-ID
CVE-2021-47603	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
In the Linux kernel, the following vulnerability has been resolved: audit: improve robustness of the audit queue handling If the audit daemon were ever to get stuck in a stopped state the kernel's kauditd_thread() could get blocked attempting to send audit records to the userspace audit daemon. With the kernel thread blocked it is possible that the audit queue could grow unbounded as certain audit record generating events must be exempt from the queue limits else the system enter a deadlock state. This patch resolves this problem by lowering the kernel thread's socket sending timeout from MAX_SCHEDULE_TIMEOUT to HZ/10 and tweaks the kauditd_send_queue() function to better manage the various audit queues when connection problems occur between the kernel and the audit daemon. With this patch, the backlog may temporarily grow beyond the defined limits when the audit daemon is stopped and the system is under heavy audit pressure, but kauditd_thread() will continue to make progress and drain the queues as it would for other connection problems. For example, with the audit daemon put into a stopped state and the system configured to audit every syscall it was still possible to shutdown the system without a kernel panic, deadlock, etc.; granted, the system was slow to shutdown but that is to be expected given the extreme pressure of recording every syscall. The timeout value of HZ/10 was chosen primarily through experimentation and this developer's "gut feeling". There is likely no one perfect value, but as this scenario is limited in scope (root privileges would be needed to send SIGSTOP to the audit daemon), it is likely not worth exposing this as a tunable at present. This can always be done at a later date if it proves necessary.
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/0d3277eabd542fb662be23696e5ec9f390d688e1 URL:https://git.kernel.org/stable/c/0d3277eabd542fb662be23696e5ec9f390d688e1 MISC:https://git.kernel.org/stable/c/4cc6badff97f74d0fce65f9784b5df3b64e4250b URL:https://git.kernel.org/stable/c/4cc6badff97f74d0fce65f9784b5df3b64e4250b MISC:https://git.kernel.org/stable/c/75fdb751f84727d614deea0571a1490c3225d83a URL:https://git.kernel.org/stable/c/75fdb751f84727d614deea0571a1490c3225d83a MISC:https://git.kernel.org/stable/c/8389f50ceb854cb437fefb9330d5024ed3c7c1f5 URL:https://git.kernel.org/stable/c/8389f50ceb854cb437fefb9330d5024ed3c7c1f5 MISC:https://git.kernel.org/stable/c/a5f4d17daf2e6cd7c1d9676b476147f6b4ac53f2 URL:https://git.kernel.org/stable/c/a5f4d17daf2e6cd7c1d9676b476147f6b4ac53f2 MISC:https://git.kernel.org/stable/c/f4b3ee3c85551d2d343a3ba159304066523f730f URL:https://git.kernel.org/stable/c/f4b3ee3c85551d2d343a3ba159304066523f730f
Assigning CNA
kernel.org
Date Record Created
20240524	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20240524)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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